ESP32 Forum

Code: Select all

#include "freertos/FreeRTOS.h"
#include "esp_wifi.h"
#include "esp_system.h"
#include "esp_event.h"
#include "esp_event_loop.h"
#include "nvs_flash.h"
#include "driver/gpio.h"
#include "driver/spi_master.h"
#include "esp_log.h"

static const char *TAG = "test";

#define MAX6675_MISO 4
#define MAX6675_SCK 27
#define MAX6675_CS 25
#define MAX6675_SPI_HOST HSPI_HOST
#define GPIO_OUTPUT_PIN_MASK  ((1<<MAX6675_CS))

static spi_device_handle_t spi_handle; // SPI handle.

esp_err_t event_handler(void *ctx, system_event_t *event)
{
    return ESP_OK;
}

static void init_gpio() {
    gpio_config_t io_conf;
    
    io_conf.intr_type = GPIO_PIN_INTR_DISABLE; //disable interrupt
    io_conf.mode = GPIO_MODE_OUTPUT; //set as output mode
    io_conf.pin_bit_mask = GPIO_OUTPUT_PIN_MASK; //bit mask of the pins
    io_conf.pull_down_en = GPIO_PULLDOWN_DISABLE; //disable pull-down mode
    io_conf.pull_up_en = GPIO_PULLUP_DISABLE;   //disable pull-up mode
    ESP_LOGD(TAG, "gpio_config");
    gpio_config(&io_conf); //configure GPIO with the given settings
    
}

void readMax6675() {
    
    float temp=0.0;
    uint16_t data,rawtemp;
    spi_bus_config_t bus_config;
    spi_device_interface_config_t dev_config;
    spi_transaction_t trans_word;
    
    ESP_LOGE(TAG, "readMax6675 start");
    
    gpio_set_level(MAX6675_CS, 1); // MAX6675_CS
    bus_config.sclk_io_num   = MAX6675_SCK; // CLK
    bus_config.mosi_io_num   = -1; // MOSI not used
    bus_config.miso_io_num   = MAX6675_MISO; // MISO
    bus_config.quadwp_io_num = -1; // not used
    bus_config.quadhd_io_num = -1; // not used
    ESP_LOGE(TAG, "spi_bus_initialize");
    
    ESP_ERROR_CHECK(spi_bus_initialize(MAX6675_SPI_HOST, &bus_config, 2));
    
    dev_config.address_bits     = 0;
    dev_config.command_bits     = 0;
    dev_config.dummy_bits       = 0;
    dev_config.mode             = 0; // SPI_MODE0
    dev_config.duty_cycle_pos   = 0;
    dev_config.cs_ena_posttrans = 0;
    dev_config.cs_ena_pretrans  = 0;
    dev_config.clock_speed_hz   = 1000000;  // 1 MHz
    dev_config.spics_io_num     = -1; // CS External
    dev_config.flags            = 0; // SPI_MSBFIRST
    dev_config.queue_size       = 100;
    dev_config.pre_cb           = NULL;
    dev_config.post_cb          = NULL;
    ESP_LOGE(TAG, "spi_bus_add_device");
    
    ESP_ERROR_CHECK(spi_bus_add_device(MAX6675_SPI_HOST, &dev_config, &spi_handle));
    
    while (1) {
        
        gpio_set_level(MAX6675_CS, 0);
        vTaskDelay(400 / portTICK_RATE_MS);
        
        rawtemp = 0x000;
        data = 0x000;
        
        trans_word.flags     = 0;
        trans_word.length    = 8 * 2; // Total data length, in bits NOT number of bytes.
        trans_word.rxlength  = 0; // (0 defaults this to the value of ``length``)
        trans_word.tx_buffer = &data;
        trans_word.rx_buffer = &rawtemp;
        ESP_ERROR_CHECK(spi_device_transmit(spi_handle, &trans_word));
        
        gpio_set_level(MAX6675_CS, 1);
        
        temp = ((((rawtemp & 0x00FF) << 8) | ((rawtemp & 0xFF00) >> 8))>>3)*25;
        
        ESP_LOGI(TAG, "readMax6675 spiReadWord=%x temp=%.2f",rawtemp,temp/100);
        
        vTaskDelay(900 / portTICK_PERIOD_MS);
    }
}

void app_main(void)
{
    nvs_flash_init();
    ESP_ERROR_CHECK( esp_event_loop_init(event_handler, NULL));
    
    init_gpio();
    readMax6675();
}

Code: Select all

uint16_t dataone[1] = {0};

Code: Select all

trans_word.rx_buffer = dataone;

Code: Select all

rawtemp = *(uint32_t *)dataone;